CA2150391A1 - Method of non-linear filtering of degraded document images - Google Patents

Method of non-linear filtering of degraded document images

Info

Publication number
CA2150391A1
CA2150391A1 CA2150391A CA2150391A CA2150391A1 CA 2150391 A1 CA2150391 A1 CA 2150391A1 CA 2150391 A CA2150391 A CA 2150391A CA 2150391 A CA2150391 A CA 2150391A CA 2150391 A1 CA2150391 A1 CA 2150391A1
Authority
CA
Canada
Prior art keywords
document images
linear filtering
degraded
degraded document
nonlinear filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CA2150391A
Other languages
French (fr)
Other versions
CA2150391C (en
Inventor
Oscar Ernesto Agazzi
Kenneth Ward Church
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
AT&T Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AT&T Corp filed Critical AT&T Corp
Publication of CA2150391A1 publication Critical patent/CA2150391A1/en
Application granted granted Critical
Publication of CA2150391C publication Critical patent/CA2150391C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/20—Image enhancement or restoration using local operators
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/20—Image preprocessing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V30/00—Character recognition; Recognising digital ink; Document-oriented image-based pattern recognition
    • G06V30/10—Character recognition
    • G06V30/14—Image acquisition
    • G06V30/148—Segmentation of character regions
    • G06V30/15—Cutting or merging image elements, e.g. region growing, watershed or clustering-based techniques
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V30/00—Character recognition; Recognising digital ink; Document-oriented image-based pattern recognition
    • G06V30/10—Character recognition

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Multimedia (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Image Processing (AREA)
  • Character Input (AREA)
  • Character Discrimination (AREA)

Abstract

A method identifies and models the distortion in a document using a two-dimensional nonlinear filter. The two-dimensional nonlinear filter is then used to improve the performance of optical character recognition systems in recognizing characters in documents that have been degraded, as for example by repeated photocopy reproductions or by fax transmission.
CA002150391A 1994-07-28 1995-05-29 Method of non-linear filtering of degraded document images Expired - Fee Related CA2150391C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US08/281,955 US5647023A (en) 1994-07-28 1994-07-28 Method of nonlinear filtering of degraded document images
US281,955 1994-07-28

Publications (2)

Publication Number Publication Date
CA2150391A1 true CA2150391A1 (en) 1996-01-29
CA2150391C CA2150391C (en) 2000-01-25

Family

ID=23079477

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002150391A Expired - Fee Related CA2150391C (en) 1994-07-28 1995-05-29 Method of non-linear filtering of degraded document images

Country Status (4)

Country Link
US (2) US5647023A (en)
EP (1) EP0694875A3 (en)
JP (1) JPH0855189A (en)
CA (1) CA2150391C (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3695217B2 (en) * 1999-04-30 2005-09-14 オムロン株式会社 Image processing apparatus and image input apparatus
US6701023B1 (en) * 1999-09-28 2004-03-02 Adobe Systems Incorporated Reducing appearance differences between coded and noncoded units of text
US7072525B1 (en) * 2001-02-16 2006-07-04 Yesvideo, Inc. Adaptive filtering of visual image using auxiliary image information
US7099399B2 (en) * 2004-01-27 2006-08-29 Crestcom, Inc. Distortion-managed digital RF communications transmitter and method therefor
US20070082617A1 (en) * 2005-10-11 2007-04-12 Crestcom, Inc. Transceiver with isolation-filter compensation and method therefor
US7598954B2 (en) * 2006-03-01 2009-10-06 Microsoft Corporation Adapting and rendering graphic effects
US8886341B1 (en) 2006-04-04 2014-11-11 Microsoft Corporation Adaptive sample-by-sample controller for under-determined systems
US7796960B1 (en) 2006-04-04 2010-09-14 Nortel Networks Limited Signal transmitter linearization
US7724840B2 (en) * 2006-12-19 2010-05-25 Crestcom, Inc. RF transmitter with predistortion and method therefor
US20080285640A1 (en) * 2007-05-15 2008-11-20 Crestcom, Inc. RF Transmitter With Nonlinear Predistortion and Method Therefor
US8928763B2 (en) 2008-12-09 2015-01-06 Abbyy Development Llc Detecting and correcting blur and defocusing
US8098303B2 (en) * 2008-12-09 2012-01-17 Abbyy Software Ltd. Method and system for restoring a motion-blurred image
RU2653461C2 (en) 2014-01-21 2018-05-08 Общество с ограниченной ответственностью "Аби Девелопмент" Glare detection in the image data frame
US8175388B1 (en) 2009-01-30 2012-05-08 Adobe Systems Incorporated Recognizing text at multiple orientations
US8423334B2 (en) * 2010-05-18 2013-04-16 Honeywell International Inc. Distributed model identification
US8494282B2 (en) * 2010-07-19 2013-07-23 Hewlett-Packard Development Company, L.P. Blur estimation
US8792748B2 (en) 2010-10-12 2014-07-29 International Business Machines Corporation Deconvolution of digital images
GB2485833A (en) * 2010-11-26 2012-05-30 S3 Res & Dev Ltd Improved OCR Using Configurable Filtering for Analysing Set Top Boxes
US9154148B2 (en) 2013-03-15 2015-10-06 Analog Devices, Inc. Clock signal error correction in a digital-to-analog converter
US9281788B2 (en) 2013-03-15 2016-03-08 Analog Devices, Inc. All digital zero-voltage switching
US9276617B2 (en) 2013-03-15 2016-03-01 Analog Devices, Inc. Radio frequency domain digital pre-distortion
US8970418B1 (en) 2013-08-19 2015-03-03 Analog Devices, Inc. High output power digital-to-analog converter system
US10056924B2 (en) 2013-08-19 2018-08-21 Analog Devices, Inc. High output power digital-to-analog converter system
US10985951B2 (en) 2019-03-15 2021-04-20 The Research Foundation for the State University Integrating Volterra series model and deep neural networks to equalize nonlinear power amplifiers
CN113822818B (en) * 2021-09-28 2022-08-12 合肥的卢深视科技有限公司 Speckle extraction method, device, electronic device, and storage medium

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02202689A (en) * 1989-02-01 1990-08-10 Fujitsu Ltd Character recognizing device
JPH02263275A (en) * 1989-04-03 1990-10-26 Kiyadeitsukusu:Kk Preparing system for register pattern of handwritten character
JP2893760B2 (en) * 1989-10-30 1999-05-24 日本電気株式会社 Pattern normalizer
US5285505A (en) * 1991-03-11 1994-02-08 International Business Machines Corporation Method and apparatus for improving prototypes of similar characters in on-line handwriting recognition
US5490223A (en) * 1993-06-22 1996-02-06 Kabushiki Kaisha Toshiba Pattern recognition apparatus

Also Published As

Publication number Publication date
US5647023A (en) 1997-07-08
JPH0855189A (en) 1996-02-27
EP0694875A2 (en) 1996-01-31
CA2150391C (en) 2000-01-25
EP0694875A3 (en) 1996-04-24
US5745597A (en) 1998-04-28

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